A2uiBasicCatalogV1.Column

interface A2uiBasicCatalogV1.Column : A2uiComponent

The A2UI "Column" component for arranging children vertically.

Schema Properties:

  • accessibility (Dynamic Custom, optional): Accessibility attributes for the column.

  • weight (Number, optional): The relative weight of the component within a Row or Column. May only be set when the component is a direct descendant of a Row or Column. See WeightProperty.

  • children (ChildList, required): Defines the children, accepting either an array of strings for a fixed set of children, or a template object to generate children from a data list.

  • justify (String Enum, optional): Defines the arrangement of children along the main axis (vertically). Valid options: "start", "center", "end", "spaceBetween", "spaceAround", "spaceEvenly", "stretch". Defaults to "start".

  • align (String Enum, optional): Defines the alignment of children along the cross axis (horizontally). Valid options: "center", "end", "start", "stretch". Defaults to "start".

Summary

Nested types

Alignment of children along the cross axis of a Column.

Arrangement of children along the main axis of a Column.

Public companion properties
DynamicA2uiProperty<A2uiBasicCatalogV1.AccessibilityAttributes>

The A2uiProperty for the "accessibility" property of a Column.
StaticA2uiProperty<A2uiBasicCatalogV1.Column.Align>

The A2uiProperty for the "align" property of a Column.
ChildListA2uiProperty

The A2uiProperty for the "children" property of a Column.
StaticA2uiProperty<A2uiBasicCatalogV1.Column.Justify>

The A2uiProperty for the "justify" property of a Column.

Public functions
open Unit
@Composable
A2uiComponentScope.Content(
    properties: A2uiComponentProperties,
    modifier: Modifier
)

Emits the UI for this component.
Unit

Renders the Column with its resolved property values.
open Boolean

Determines whether this component is ready to be rendered.

Public properties
open String

A semantic description of the component's behavior and purpose.
open String

The unique string identifier for this component type (e.g., "Text", "Button").
open List<A2uiProperty<*>>

The list of typed properties expected by this component.

Public companion properties

AccessibilityProperty

Added in 1.0.0-alpha01
val AccessibilityProperty: DynamicA2uiProperty<A2uiBasicCatalogV1.AccessibilityAttributes>

The A2uiProperty for the "accessibility" property of a Column.

AlignProperty

Added in 1.0.0-alpha01
val AlignProperty: StaticA2uiProperty<A2uiBasicCatalogV1.Column.Align>

The A2uiProperty for the "align" property of a Column.

ChildrenProperty

Added in 1.0.0-alpha01
val ChildrenProperty: ChildListA2uiProperty

The A2uiProperty for the "children" property of a Column.

JustifyProperty

Added in 1.0.0-alpha01
val JustifyProperty: StaticA2uiProperty<A2uiBasicCatalogV1.Column.Justify>

The A2uiProperty for the "justify" property of a Column.

Public functions

A2uiComponentScope.Content

@Composable
open fun A2uiComponentScope.Content(
    properties: A2uiComponentProperties,
    modifier: Modifier
): Unit

Emits the UI for this component.

This function is invoked within the A2uiComponentScope, which provides access to extensions for evaluating reactive data bindings, rendering nested children, dispatching user actions, and reporting runtime errors.

Parameters
properties: A2uiComponentProperties

The stable properties wrapper from which to extract static payloads or bind dynamic data paths.
modifier: Modifier

The Modifier applied to the root of this component's layout.

A2uiComponentScope.TypedContent

@Composable
fun A2uiComponentScope.TypedContent(
    children: List<A2uiComponentReference>,
    justify: A2uiBasicCatalogV1.Column.Justify,
    align: A2uiBasicCatalogV1.Column.Align,
    accessibility: A2uiBasicCatalogV1.AccessibilityAttributes?,
    modifier: Modifier
): Unit

Renders the Column with its resolved property values.

Parameters
children: List<A2uiComponentReference>

list of child A2uiComponentReferences to render in this column
justify: A2uiBasicCatalogV1.Column.Justify

Justify arrangement of children along the vertical main axis
align: A2uiBasicCatalogV1.Column.Align

Align alignment of children along the horizontal cross axis
accessibility: A2uiBasicCatalogV1.AccessibilityAttributes?

accessibility attributes for the column
modifier: Modifier

Modifier to apply to the layout

A2uiComponentScope.isReady

@Composable
open fun A2uiComponentScope.isReady(properties: A2uiComponentProperties): Boolean

Determines whether this component is ready to be rendered.

This is evaluated during component state resolution to determine if the component should transition from the androidx.a2ui.compose.runtime.A2uiComponentState.Loading state to the androidx.a2ui.compose.runtime.A2uiComponentState.Success state. The readiness is automatically re-evaluated when any reactive state read in this composable function changes (such as dynamic data bindings observed via properties.bind(...)).

By default, components are considered instantly ready. Override this method to support progressive rendering—for example, returning false until a required dynamic data binding (like an image URL or text string) has been successfully resolved from the surface's data model.

Parameters
properties: A2uiComponentProperties

The stable properties wrapper provided by the A2UI protocol.
Returns
Boolean

true if the component is fully ready to be composed, false if it is still loading.

Public properties

description

open val description: String

A semantic description of the component's behavior and purpose.

This is included in the generated schema to help the agent understand when and how it should output this component.

name

open val name: String

The unique string identifier for this component type (e.g., "Text", "Button").

This matches the "component" field in the A2UI protocol's component payloads and is used by the framework to route incoming payloads to this specific implementation.

Note: This name must be unique within an A2uiCatalog.

properties

open val properties: List<A2uiProperty<*>>

The list of typed properties expected by this component.

The properties serve two purposes:

  1. To automatically generate the component's JSON schema for the agent.

  2. To serve as type-safe tokens for extracting payloads or resolving dynamic data bindings from A2uiComponentProperties at runtime.